CN112230373B

CN112230373B - Image pickup optical lens

Info

Publication number: CN112230373B
Application number: CN202011192711.5A
Authority: CN
Inventors: 朱峰
Original assignee: AAC Optics Suzhou Co Ltd
Current assignee: AAC Optics Suzhou Co Ltd
Priority date: 2020-10-30
Filing date: 2020-10-30
Publication date: 2022-03-01
Anticipated expiration: 2040-10-30
Also published as: WO2022088249A1; US20220137341A1; JP2022073849A; CN112230373A; JP6903217B1

Abstract

The invention relates to the field of optical lenses, and discloses an image pickup optical lens, which sequentially comprises from an object side to an image side: the first lens element comprises a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element, wherein the first lens element has positive refractive power; the total optical length of the imaging optical lens is TTL, the focal length of the imaging optical lens is f, the focal length of the second lens element is f2, the central curvature radius of the object-side surface of the seventh lens element is R13, and the central curvature radius of the image-side surface of the seventh lens element is R14, and the following relations are satisfied: f/TTL is more than or equal to 0.95; f2/f is more than or equal to 3.00 and less than or equal to 5.50; 3.00 is less than or equal to (R13+ R14)/(R13-R14) is less than or equal to 25.00. The camera optical lens provided by the invention has good optical performance, and also meets the design requirements of long focal length and ultra-thinness.

Description

Image pickup optical lens

Technical Field

The present invention relates to the field of optical lenses, and more particularly, to an imaging optical lens suitable for portable terminal devices such as smart phones and digital cameras, and imaging apparatuses such as monitors and PC lenses.

Background

In recent years, with the rise of smart phones, the demand of miniaturized camera lenses is increasing, and the photosensitive devices of general camera lenses are not limited to two types, namely, a Charge Coupled Device (CCD) or a Complementary Metal-Oxide Semiconductor (CMOS) Device, and due to the refinement of Semiconductor manufacturing technology, the pixel size of the photosensitive devices is reduced, and in addition, the current electronic products are developed in a form of being excellent in function, light, thin, short and small, so that the miniaturized camera lenses with good imaging quality are the mainstream in the current market.

In order to obtain better imaging quality, the lens mounted on the mobile phone camera conventionally adopts three-piece, four-piece, or even five-piece or six-piece lens structures. However, with the development of technology and the increasing of diversified demands of users, under the condition that the pixel area of the photosensitive device is continuously reduced and the requirement of the system for the imaging quality is continuously improved, an eight-piece lens structure gradually appears in the lens design, although a common eight-piece lens has good optical performance, the focal power, the lens interval and the lens shape setting of the eight-piece lens still have certain irrationality, so that the lens structure can not meet the design requirements of long focal length and ultra-thinness while having good optical performance.

Therefore, it is necessary to provide an imaging optical lens having excellent optical performance and satisfying the design requirements of long focal length and thinness.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide an imaging optical lens that has excellent optical performance and satisfies design requirements for a long focal length and an ultra-thin profile.

To solve the above-mentioned problems, an embodiment of the present invention provides an imaging optical lens, in order from an object side to an image side, comprising: the first lens element comprises a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element, wherein the first lens element has positive refractive power; the total optical length of the imaging optical lens is TTL, the focal length of the imaging optical lens is f, the focal length of the second lens element is f2, the central curvature radius of the object-side surface of the seventh lens element is R13, and the central curvature radius of the image-side surface of the seventh lens element is R14, and the following relations are satisfied: f/TTL is more than or equal to 0.95; f2/f is more than or equal to 3.00 and less than or equal to 5.50; 3.00 is less than or equal to (R13+ R14)/(R13-R14) is less than or equal to 25.00.

Preferably, the seventh lens has an on-axis thickness of d13, the eighth lens has an on-axis thickness of d15, and the following relationship is satisfied: d13/d15 is more than or equal to 1.50 and less than or equal to 3.60.

Preferably, the focal length of the first lens is f1, the central radius of curvature of the object-side surface of the first lens is R1, the central radius of curvature of the image-side surface of the first lens is R2, the on-axis thickness of the first lens is d1, and the following relationship is satisfied: f1/f is more than or equal to 0.25 and less than or equal to 1.08; -2.48 ≤ (R1+ R2)/(R1-R2) ≤ 0.36; d1/TTL is more than or equal to 0.05 and less than or equal to 0.16.

Preferably, the central radius of curvature of the object-side surface of the second lens is R3, the central radius of curvature of the image-side surface of the second lens is R4, the on-axis thickness of the second lens is d3, and the following relationship is satisfied: -19.00 ≤ (R3+ R4)/(R3-R4) 0.48; d3/TTL is more than or equal to 0.02 and less than or equal to 0.07.

Preferably, the focal length of the third lens is f3, the central radius of curvature of the object-side surface of the third lens is R5, the central radius of curvature of the image-side surface of the third lens is R6, the on-axis thickness of the third lens is d5, and the following relationship is satisfied: -91.89 ≤ f3/f ≤ 1.99; -62.08 (R5+ R6)/(R5-R6) is less than or equal to 0.61; d5/TTL is more than or equal to 0.02 and less than or equal to 0.09.

Preferably, the focal length of the fourth lens is f4, the central radius of curvature of the object-side surface of the fourth lens is R7, the central radius of curvature of the image-side surface of the fourth lens is R8, the on-axis thickness of the fourth lens is d7, and the following relationship is satisfied: f4/f is not less than 1.01 and not more than-0.30; -1.17 ≤ (R7+ R8)/(R7-R8) ≤ 0.23; d7/TTL is more than or equal to 0.02 and less than or equal to 0.06.

Preferably, the focal length of the fifth lens is f5, the central radius of curvature of the object-side surface of the fifth lens is R9, the central radius of curvature of the image-side surface of the fifth lens is R10, the on-axis thickness of the fifth lens is d9, and the following relationship is satisfied: f5/f is more than or equal to 1.02 and less than or equal to 18.34; 9.21-39.19 (R9+ R10)/(R9-R10); d9/TTL is more than or equal to 0.02 and less than or equal to 0.15.

Preferably, the focal length of the sixth lens is f6, the central radius of curvature of the object-side surface of the sixth lens is R11, the central radius of curvature of the image-side surface of the sixth lens is R12, the on-axis thickness of the sixth lens is d11, and the following relationship is satisfied: f6/f is more than or equal to 0.51 and less than or equal to 4.54; (R11+ R12)/(R11-R12) is not more than 0.79 and not more than 6.41; d11/TTL is more than or equal to 0.02 and less than or equal to 0.15.

Preferably, the focal length of the seventh lens is f7, the on-axis thickness of the seventh lens is d13, and the following relation is satisfied: f7/f is more than or equal to 0.76 and less than or equal to 5.60; d13/TTL is more than or equal to 0.03 and less than or equal to 0.19.

Preferably, the focal length of the eighth lens is f8, the central radius of curvature of the object-side surface of the eighth lens is R15, the central radius of curvature of the image-side surface of the eighth lens is R16, the on-axis thickness of the eighth lens is d15, and the following relationship is satisfied: f8/f is more than or equal to-1.77 and less than or equal to-0.48; (R15+ R16)/(R15-R16) is not more than 0.60 and not more than 3.41; d15/TTL is more than or equal to 0.02 and less than or equal to 0.06.

Preferably, the image height of the imaging optical lens is IH, and the following relation is satisfied: f/IH is more than or equal to 2.58.

Preferably, the image height of the imaging optical lens is IH, and the following relation is satisfied: TTL/IH is less than or equal to 2.85.

The invention has the beneficial effects that: the imaging optical lens of the present invention has excellent optical characteristics, long focal length and ultra-thin characteristics, and is particularly suitable for a mobile phone imaging lens assembly and a WEB imaging lens which are composed of high-pixel imaging elements such as a CCD and a CMOS.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without inventive efforts, wherein:

fig. 1 is a schematic configuration diagram of an imaging optical lens according to a first embodiment of the present invention;

FIG. 2 is a schematic axial aberration diagram of the imaging optical lens of FIG. 1;

fig. 3 is a schematic diagram of chromatic aberration of magnification of the imaging optical lens shown in fig. 1;

FIG. 4 is a schematic view of curvature of field and distortion of the imaging optical lens of FIG. 1;

fig. 5 is a schematic configuration diagram of an imaging optical lens according to a second embodiment of the present invention;

FIG. 6 is a schematic axial aberration diagram of the imaging optical lens of FIG. 5;

fig. 7 is a schematic diagram of chromatic aberration of magnification of the imaging optical lens shown in fig. 5;

FIG. 8 is a schematic view of curvature of field and distortion of the imaging optical lens of FIG. 5;

fig. 9 is a schematic configuration diagram of an imaging optical lens according to a third embodiment of the present invention;

fig. 10 is a schematic view of axial aberrations of the image pickup optical lens shown in fig. 9;

fig. 11 is a schematic diagram of chromatic aberration of magnification of the imaging optical lens shown in fig. 9;

fig. 12 is a schematic view of curvature of field and distortion of the imaging optical lens shown in fig. 9.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, it will be appreciated by those of ordinary skill in the art that numerous technical details are set forth in order to provide a better understanding of the present invention in its various embodiments. However, the technical solution claimed in the present invention can be implemented without these technical details and various changes and modifications based on the following embodiments.

(first embodiment)

Referring to the drawings, the present invention provides an image pickup optical lens 10. Fig. 1 is a schematic structural diagram of an imaging optical lens 10 according to a first embodiment of the present invention, where the imaging optical lens 10 includes eight lenses. Specifically, the imaging optical lens 10 includes, in order from an object side to an image side: the stop S1, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8. An optical element such as an optical filter (filter) GF may be disposed between the eighth lens L8 and the image plane Si.

In this embodiment, the first lens element L1 has positive refractive power, the second lens element L2 has positive refractive power, the third lens element L3 has positive refractive power, the fourth lens element L4 has negative refractive power, the fifth lens element L5 has positive refractive power, the sixth lens element L6 has positive refractive power, the seventh lens element L7 has positive refractive power, and the eighth lens element L8 has negative refractive power. It is understood that in other embodiments, the third lens element L3, the fourth lens element L4, the fifth lens element L5, the sixth lens element L6, the seventh lens element L7 and the eighth lens element L8 have other refractive powers.

In this embodiment, the first lens element L1 has positive refractive power, which is beneficial for improving the performance of the optical system.

In this embodiment, the first lens L1 is made of plastic, the second lens L2 is made of plastic, the third lens L3 is made of plastic, the fourth lens L4 is made of plastic, the fifth lens L5 is made of plastic, the sixth lens L6 is made of plastic, the seventh lens L7 is made of plastic, and the eighth lens L8 is made of plastic. In other embodiments, the lenses may be made of other materials.

In the present embodiment, it is defined that the total optical length of the imaging optical lens 10 is TTL, the focal length of the imaging optical lens 10 is f, the focal length of the second lens L2 is f2, the center radius of curvature of the object-side surface of the seventh lens L7 is R13, and the center radius of curvature of the image-side surface of the seventh lens L7 is R14, and the following relationships are satisfied:

0.95≤f/TTL； (1)

3.00≤f2/f≤5.50； (2)

3.00≤(R13+R14)/(R13-R14)≤25.00。 (3)

the relation (1) specifies the ratio of the focal length f of the imaging optical lens 10 to the total optical length TTL of the imaging optical lens 10, and when the relation (1) satisfies the condition, the imaging optical lens 10 has a longer focal length at the same length.

The relation (2) specifies the ratio of the focal length f2 of the second lens L2 to the focal length f of the imaging optical lens 10, and can effectively balance the spherical aberration and the amount of curvature of field of the system. Preferably, 3.08. ltoreq. f 2/f. ltoreq.5.45 is satisfied.

The relation (3) defines the shape of the seventh lens L7, and the degree of deflection of the light passing through the lens can be alleviated within the range of the relation (3), thereby effectively reducing the aberration. Preferably, 3.03 ≦ (R13+ R14)/(R13-R14) ≦ 24.76 is satisfied.

Defining the on-axis thickness of the seventh lens L7 to be d13 and the on-axis thickness of the eighth lens L8 to be d15, the following relation is satisfied: d13/d15 is more than or equal to 1.50 and less than or equal to 3.60. The ratio of the on-axis thickness d13 of the seventh lens L7 to the on-axis thickness d15 of the eighth lens L8 is defined, and contributes to the reduction of the total optical length of the system within the range of the relational expression, thereby achieving the effect of making the system ultra-thin. Preferably, 1.63. ltoreq. d13/d 15. ltoreq.3.56 is satisfied.

In this embodiment, the object-side surface of the first lens element L1 is convex at the paraxial region, and the image-side surface thereof is concave at the paraxial region.

Defining the focal length of the first lens L1 as f1, and the focal length of the image pickup optical lens 10 as f, the following relations are satisfied: f1/f is 0.25 ≦ 1.08, and the ratio of the focal length f1 of the first lens L1 to the focal length f of the imaging optical lens 10 is specified. Within the predetermined range, the first lens element L1 has a proper positive refractive power, which is beneficial to reducing system aberration and to making the lens barrel ultrathin. Preferably, 0.41. ltoreq. f 1/f. ltoreq.0.86 is satisfied.

The central curvature radius of an object side surface of the first lens L1 is defined to be R1, the central curvature radius of an image side surface of the first lens L1 is defined to be R2, and the following relational expressions are satisfied: 2.48 ≦ (R1+ R2)/(R1-R2) ≦ -0.36, and the shape of the first lens L1 is controlled appropriately so that the first lens L1 can correct the system spherical aberration effectively. Preferably, it satisfies-1.55 ≦ (R1+ R2)/(R1-R2) ≦ -0.45.

Defining the on-axis thickness of the first lens L1 as d1, the total optical length of the image pickup optical lens 10 as TTL, and satisfying the following relation: d1/TTL is more than or equal to 0.05 and less than or equal to 0.16, and ultra-thinning is facilitated in the condition formula range. Preferably, 0.08. ltoreq. d 1/TTL. ltoreq.0.13 is satisfied.

In this embodiment, the object-side surface of the second lens element L2 is convex at the paraxial region, and the image-side surface is concave at the paraxial region.

The central curvature radius of the object side surface of the second lens L2 is defined as R3, the central curvature radius of the image side surface of the second lens L2 is defined as R4, and the following relations are satisfied: the shape of the second lens L2 is defined to be (R3+ R4)/(R3-R4) to be not more than 19.00 and not more than 0.48, and the problem of chromatic aberration on the axis can be corrected favorably as the lens becomes thinner when the shape is within the range. Preferably, it satisfies-11.88 ≦ (R3+ R4)/(R3-R4). ltoreq.0.39.

Defining the on-axis thickness of the second lens L2 as d3, the total optical length of the image pickup optical lens 10 as TTL, and satisfying the following relation: d3/TTL is more than or equal to 0.02 and less than or equal to 0.07, and ultra-thinning is favorably realized within the range of conditional expressions. Preferably, 0.03. ltoreq. d 3/TTL. ltoreq.0.05 is satisfied.

In this embodiment, the object-side surface of the third lens element L3 is convex at the paraxial region, and the image-side surface is convex at the paraxial region.

Defining the focal length of the third lens L3 as f3 and the focal length of the image pickup optical lens 10 as f, the following relations are satisfied: 91.89 ≦ f3/f ≦ 1.99, which allows better imaging quality and lower sensitivity of the system by a reasonable distribution of the powers. Preferably, it satisfies-57.43. ltoreq. f 3/f. ltoreq.1.59.

The central curvature radius of the object side surface of the third lens L3 is defined as R5, the central curvature radius of the image side surface of the third lens L3 is defined as R6, and the following relations are satisfied: the (R5+ R6)/(R5-R6) is less than or equal to 0.61 and is more than or equal to-62.08, the shape of the third lens L3 can be effectively controlled, the forming of the third lens L3 is facilitated, the deflection degree of light rays passing through the lens can be alleviated within the range specified by the conditional expression, and the aberration can be effectively reduced. Preferably, it satisfies-38.80 ≦ (R5+ R6)/(R5-R6). ltoreq.0.49.

Defining the on-axis thickness of the third lens L3 as d5, the total optical length of the imaging optical lens system 10 as TTL, and satisfying the following relation: d5/TTL is more than or equal to 0.02 and less than or equal to 0.09, and ultra-thinning is favorably realized within the range of conditional expressions. Preferably, 0.04. ltoreq. d 5/TTL. ltoreq.0.07 is satisfied.

In the present embodiment, the object-side surface of the fourth lens element L4 is concave at the paraxial region, and the image-side surface is concave at the paraxial region.

Defining the focal length of the fourth lens L4 as f4, and the focal length of the image pickup optical lens 10 as f, the following relations are satisfied: f4/f is 1.01-0.30, and the ratio of the focal length f4 of the fourth lens L4 to the focal length f of the image pickup optical lens 10 is specified, which contributes to the improvement of the optical system performance within the conditional expression. Preferably, it satisfies-0.63. ltoreq. f 4/f. ltoreq-0.38.

The central curvature radius of the object side surface of the fourth lens L4 is defined as R7, the central curvature radius of the image side surface of the fourth lens L4 is defined as R8, and the following relations are satisfied: -1.17 ≦ (R7+ R8)/(R7-R8) ≦ -0.23, and defines the shape of the fourth lens L4, which is advantageous for correcting the aberration of the off-axis view angle and the like with the progress of the ultra-thinning when in the range. Preferably, it satisfies-0.73 ≦ (R7+ R8)/(R7-R8) ≦ -0.28.

Defining the on-axis thickness of the fourth lens L4 as d7, the total optical length of the image pickup optical lens 10 as TTL, and satisfying the following relation: d7/TTL is more than or equal to 0.02 and less than or equal to 0.06, and ultra-thinning is facilitated in the conditional expression range. Preferably, 0.03. ltoreq. d 7/TTL. ltoreq.0.04 is satisfied.

In this embodiment, the object-side surface of the fifth lens element L5 is convex at the paraxial region, and the image-side surface thereof is concave at the paraxial region.

Defining the focal length of the fifth lens L5 as f5, and the focal length of the image pickup optical lens 10 as f, the following relations are satisfied: 1.02 is less than or equal to f5/f is less than or equal to 18.34, and the definition of the fifth lens L5 can effectively make the light ray angle of the shooting optical lens 10 smooth and reduce tolerance sensitivity. Preferably, 1.63. ltoreq. f 5/f. ltoreq.14.67 is satisfied.

The central curvature radius of the object side surface of the fifth lens L5 is defined as R9, the central curvature radius of the image side surface of the fifth lens L5 is defined as R10, and the following relations are satisfied: 9.21 ≦ (R9+ R10)/(R9-R10) ≦ 39.19, and defines the shape of the fifth lens L5, which is advantageous for correcting the off-axis view angle aberration and the like with the progress of thinning when the conditions are within the range. Preferably, it satisfies-5.76. ltoreq. (R9+ R10)/(R9-R10). ltoreq.31.35.

Defining the on-axis thickness of the fifth lens L5 as d9, the total optical length of the imaging optical lens system 10 as TTL, and satisfying the following relation: d9/TTL is more than or equal to 0.02 and less than or equal to 0.15, and ultra-thinning is facilitated in the conditional expression range. Preferably, 0.03. ltoreq. d 9/TTL. ltoreq.0.12 is satisfied.

In this embodiment, the object-side surface of the sixth lens element L6 is concave at the paraxial region, and the image-side surface thereof is convex at the paraxial region.

Defining the focal length of the sixth lens L6 as f6 and the focal length of the image pickup optical lens 10 as f, the following relations are satisfied: f6/f is more than or equal to 0.51 and less than or equal to 4.54, and the system has better imaging quality and lower sensitivity through reasonable distribution of the focal power. Preferably, 0.81. ltoreq. f 6/f. ltoreq.3.63 is satisfied.

The center radius of curvature of the object-side surface of the sixth lens L6 is defined as R11, the center radius of curvature of the image-side surface of the sixth lens L6 is defined as R12, the following relational expression 0.79 ≦ (R11+ R12)/(R11-R12) ≦ 6.41 is satisfied, and the shape of the sixth lens L6 is defined, and when the conditions are within the range, it is advantageous to correct off-axis view aberration and the like as the thickness becomes thinner. Preferably, 1.26. ltoreq. (R11+ R12)/(R11-R12). ltoreq.5.13 is satisfied.

Defining the on-axis thickness of the sixth lens L6 as d11, the total optical length of the imaging optical lens system 10 as TTL, and satisfying the following relation: d11/TTL is more than or equal to 0.02 and less than or equal to 0.15, and ultra-thinning is facilitated in the conditional expression range. Preferably, 0.03. ltoreq. d 11/TTL. ltoreq.0.12 is satisfied.

In this embodiment, the object-side surface of the seventh lens element L7 is concave at the paraxial region, and the image-side surface thereof is convex at the paraxial region.

Defining the focal length of the seventh lens L7 as f7 and the focal length of the image pickup optical lens 10 as f, the following relations are satisfied: f7/f is more than or equal to 0.76 and less than or equal to 5.60, and the system has better imaging quality and lower sensitivity through reasonable distribution of the focal power. Preferably, 1.22. ltoreq. f 7/f. ltoreq.4.48 is satisfied.

Defining the on-axis thickness of the seventh lens L7 as d13, the total optical length of the imaging optical lens system 10 as TTL, and satisfying the following relation: d13/TTL is more than or equal to 0.03 and less than or equal to 0.19, and ultra-thinning is favorably realized within the range of conditional expressions. Preferably, 0.05. ltoreq. d 13/TTL. ltoreq.0.15 is satisfied.

In this embodiment, the object-side surface of the eighth lens element L8 is convex at the paraxial region, and the image-side surface thereof is concave at the paraxial region.

Defining the focal length of the eighth lens L8 as f8, and the focal length of the image pickup optical lens 10 as f, the following relations are satisfied: 1.77 ≦ f8/f ≦ -0.48, allowing better imaging quality and lower sensitivity of the system through reasonable distribution of optical power. Preferably, it satisfies-1.10. ltoreq. f 8/f. ltoreq-0.61.

The central curvature radius of the object side surface of the eighth lens L8 is defined as R15, the central curvature radius of the image side surface of the eighth lens L8 is defined as R16, and the following relations are satisfied: the (R15+ R16)/(R15-R16) is 0.60 or more and 3.41 or less, and the shape of the eighth lens L8 is defined, and when the conditions are within the range, the problem such as aberration of the off-axis picture angle is favorably corrected along with the development of ultra-thinning. Preferably, 0.97 ≦ (R15+ R16)/(R15-R16) ≦ 2.73.

Defining the on-axis thickness of the eighth lens element L8 as d15, the total optical length of the imaging optical lens system 10 as TTL, and satisfying the following relationship: d15/TTL is more than or equal to 0.02 and less than or equal to 0.06, and ultra-thinning is facilitated in the conditional expression range. Preferably, 0.03. ltoreq. d 15/TTL. ltoreq.0.04 is satisfied.

It is understood that in other embodiments, the surface shapes of the object-side surface and the image-side surface of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8 at the paraxial region may be set to other concave and convex distribution cases.

In the present embodiment, the image height of the imaging optical lens 10 is IH, the focal length of the imaging optical lens 10 is f, and the following relational expression is satisfied: f/IH is larger than or equal to 2.58, so that the image pickup optical lens 10 has a long focal length.

In the present embodiment, the image height of the image pickup optical lens 10 is IH, the total optical length of the image pickup optical lens 10 is TTL, and the following relational expression is satisfied: TTL/IH is less than or equal to 2.85, thereby being beneficial to realizing ultra-thinning.

In the present embodiment, the focal length of the imaging optical lens 10 is f, and the combined focal length of the first lens L1 and the second lens L2 is f12, which satisfy the following relation: f12/f is not less than 0.23 and not more than 0.95, and within the range of the conditional expression, the aberration and distortion of the image pickup optical lens 10 can be eliminated, and the back focal length of the image pickup optical lens 10 can be suppressed, so as to keep the miniaturization of the image lens system. Preferably, 0.36. ltoreq. f 12/f. ltoreq.0.76 is satisfied.

When the above relationship is satisfied, the imaging optical lens 10 has good optical performance and can satisfy the design requirements of long focal length and ultra-thinness; in accordance with the characteristics of the imaging optical lens 10, the imaging optical lens 10 is particularly suitable for a mobile phone imaging lens module and a WEB imaging lens which are configured by an imaging element such as a high-pixel CCD or a CMOS.

The image pickup optical lens 10 of the present invention will be explained below by way of example. The symbols described in the respective examples are as follows. The unit of focal length, on-axis distance, center curvature radius, on-axis thickness, position of the reverse curvature point and the position of the stagnation point is mm.

TTL: the total optical length (on-axis distance from the object side surface of the first lens L1 to the image plane Si) is in mm;

aperture value FNO: is the ratio of the effective focal length and the entrance pupil diameter of the imaging optical lens.

Preferably, the object side surface and/or the image side surface of the lens may be further provided with an inflection point and/or a stagnation point to meet the requirement of high-quality imaging.

Tables 1 and 2 show design data of the imaging optical lens 10 according to the first embodiment of the present invention.

[ TABLE 1 ]

Wherein each symbol has the following meaning.

S1: an aperture;

r: a radius of curvature at the center of the optical surface;

r1: the center radius of curvature of the object side of the first lens L1;

r2: the central radius of curvature of the image-side surface of the first lens L1;

r3: the center radius of curvature of the object side of the second lens L2;

r4: the central radius of curvature of the image-side surface of the second lens L2;

r5: the center radius of curvature of the object side of the third lens L3;

r6: the central radius of curvature of the image-side surface of the third lens L3;

r7: the center radius of curvature of the object side of the fourth lens L4;

r8: the central radius of curvature of the image-side surface of the fourth lens L4;

r9: the center radius of curvature of the object side of the fifth lens L5;

r10: the center radius of curvature of the image-side surface of the fifth lens L5;

r11: the center radius of curvature of the object side of the sixth lens L6;

r12: the center radius of curvature of the image-side surface of the sixth lens L6;

r13: the center radius of curvature of the object side of the seventh lens L7;

r14: the central radius of curvature of the image-side surface of the seventh lens L7;

r15: the center radius of curvature of the object side of the eighth lens L8;

r16: the center radius of curvature of the image-side surface of the eighth lens L8;

r17: the central radius of curvature of the object side of the optical filter GF;

r18: the center radius of curvature of the image side of the optical filter GF;

d: on-axis thickness of the lenses, on-axis distance between the lenses;

d 0: the on-axis distance of the stop S1 to the object-side surface of the first lens L1;

d 1: the on-axis thickness of the first lens L1;

d 2: the on-axis distance from the image-side surface of the first lens L1 to the object-side surface of the second lens L2;

d 3: the on-axis thickness of the second lens L2;

d 4: the on-axis distance from the image-side surface of the second lens L2 to the object-side surface of the third lens L3;

d 5: the on-axis thickness of the third lens L3;

d 6: the on-axis distance from the image-side surface of the third lens L3 to the object-side surface of the fourth lens L4;

d 7: the on-axis thickness of the fourth lens L4;

d 8: an on-axis distance from an image-side surface of the fourth lens L4 to an object-side surface of the fifth lens L5;

d 9: the on-axis thickness of the fifth lens L5;

d 10: an on-axis distance from an image-side surface of the fifth lens L5 to an object-side surface of the sixth lens L6;

d 11: the on-axis thickness of the sixth lens L6;

d 12: an on-axis distance from the image-side surface of the sixth lens L6 to the object-side surface of the seventh lens L7;

d 13: the on-axis thickness of the seventh lens L7;

d 14: an on-axis distance from the image-side surface of the seventh lens L7 to the object-side surface of the eighth lens L8;

d 15: the on-axis thickness of the eighth lens L8;

d 16: the on-axis distance from the image-side surface of the eighth lens L8 to the object-side surface of the optical filter GF;

d 17: on-axis thickness of the optical filter GF;

d 18: the axial distance from the image side surface of the optical filter GF to the image surface Si;

nd: the refractive index of the d-line;

nd 1: the refractive index of the d-line of the first lens L1;

nd 2: the refractive index of the d-line of the second lens L2;

nd 3: the refractive index of the d-line of the third lens L3;

nd 4: the refractive index of the d-line of the fourth lens L4;

nd 5: the refractive index of the d-line of the fifth lens L5;

nd 6: the refractive index of the d-line of the sixth lens L6;

nd 7: the refractive index of the d-line of the seventh lens L7;

nd 8: the refractive index of the d-line of the eighth lens L8;

ndg: the refractive index of the d-line of the optical filter GF;

vd: an Abbe number;

v 1: abbe number of the first lens L1;

v 2: abbe number of the second lens L2;

v 3: abbe number of the third lens L3;

v 4: abbe number of the fourth lens L4;

v 5: abbe number of the fifth lens L5;

v 6: abbe number of the sixth lens L6;

v 7: abbe number of the seventh lens L7;

v 8: abbe number of the eighth lens L8;

vg: abbe number of the optical filter GF.

Table 2 shows aspherical surface data of each lens in the imaging optical lens 10 according to the first embodiment of the present invention.

[ TABLE 2 ]

Wherein k is a conic coefficient, and A4, A6, A8, A10, A12, A14, A16, A18, A20 are aspheric coefficients.

y＝(x²/R)/{1+[1-(k+1)(x²/R²)]^1/2}+A4x⁴+A6x⁶+A8x⁸+A10x¹⁰+A12x¹²+A14x¹⁴+A16x¹⁶+A18x¹⁸+A20x²⁰ (4)

Where x is the perpendicular distance of a point on the aspherical curve to the optical axis and y is the aspherical depth. (the perpendicular distance between the point on the aspheric surface at x from the optical axis and the tangent plane tangent to the vertex on the aspheric surface optical axis).

For convenience, the aspherical surface of each lens surface uses the aspherical surface shown in the above formula (4). However, the present invention is not limited to the aspherical polynomial form expressed by this formula (4).

Tables 3 and 4 show the inflection point and stagnation point design data of each lens in the imaging optical lens 10 according to the first embodiment of the present invention. Wherein P1R1 and P1R2 represent the object-side surface and the image-side surface of the first lens L1, P2R1 and P2R2 represent the object-side surface and the image-side surface of the second lens L2, P3R1 and P3R2 represent the object-side surface and the image-side surface of the third lens L3, P4R1 and P4R2 represent the object-side surface and the image-side surface of the fourth lens L4, P5R1 and P5R2 represent the object-side surface and the image-side surface of the fifth lens L5, P6R1 and P6R2 represent the object-side surface and the image-side surface of the sixth lens L6, P7R1 and P7R2 represent the object-side surface and the image-side surface of the seventh lens L7, and P8R1 and P8R2 represent the object-side surface and the image-side surface of the eighth lens L8, respectively. The "inflection point position" field correspondence data is a vertical distance from an inflection point set on each lens surface to the optical axis of the image pickup optical lens 10. The "stagnation point position" field corresponding data is the vertical distance from the stagnation point set on each lens surface to the optical axis of the imaging optical lens 10.

[ TABLE 3 ]

	Number of points of inflection	Position of reverse curvature 1	Position of reverse curvature 2
				P1R1	1	1.715	/
P1R2	1	1.505	/
				P2R1	2	1.375	1.565
P2R2	2	1.255	1.525
				P3R1	2	0.605	0.695
P3R2	1	1.195	/
				P4R1	0	/	/
P4R2	0	/	/
				P5R1	1	0.835	/
P5R2	1	0.765	/
				P6R1	0	/	/
P6R2	1	1.765	/
				P7R1	1	1.855	/
P7R2	0	/	/
				P8R1	2	0.365	1.935
P8R2	2	0.585	2.505

[ TABLE 4 ]

Fig. 2 and 3 are schematic diagrams showing axial aberrations and chromatic aberration of magnification of light having wavelengths of 650nm, 610nm, 555nm, 510nm, and 470nm passing through the imaging optical lens 10 according to the first embodiment. Fig. 4 is a schematic view showing curvature of field and distortion of light having a wavelength of 555nm after passing through the imaging optical lens 10 according to the first embodiment, where S is curvature of field in the sagittal direction and T is curvature of field in the tangential direction in fig. 4.

Table 13 shown later shows values corresponding to the parameters defined in the conditional expressions, for each of the numerical values in the first, second, and third embodiments.

As shown in table 13, the first embodiment satisfies each conditional expression.

In the present embodiment, the imaging optical lens 10 has an entrance pupil diameter ENPD of 3.388mm, a full field image height IH of 3.000mm, and a diagonal field angle FOV of 40.00 °, and the imaging optical lens 10 satisfies the design requirements of a long focal length and a slimness, and has excellent optical characteristics with on-axis and off-axis chromatic aberration sufficiently corrected.

(second embodiment)

Fig. 5 is a schematic structural diagram of an imaging optical lens 20 according to a second embodiment of the present invention, which is basically the same as the first embodiment, and the same reference numerals as the first embodiment, and only differences will be described below.

In this embodiment, the third lens element L3 with negative refractive power has a convex image-side surface of the first lens element L1 at paraxial region, a convex image-side surface of the second lens element L2 at paraxial region, and a concave object-side surface of the third lens element L3 at paraxial region.

Tables 5 and 6 show design data of the imaging optical lens 20 according to the second embodiment of the present invention.

[ TABLE 5 ]

Table 6 shows aspherical surface data of each lens in the imaging optical lens 20 according to the second embodiment of the present invention.

[ TABLE 6 ]

Tables 7 and 8 show the inflection point and stagnation point design data of each lens in the imaging optical lens 20 according to the second embodiment of the present invention.

[ TABLE 7 ]

	Number of points of inflection	Position of reverse curvature 1	Position of reverse curvature 2	Position of reverse curvature 3
					P1R1	0	/	/	/
P1R2	1	0.945	/	/
					P2R1	1	0.815	/	/
P2R2
		0	/	/	/
P3R1						1	0.895	/	/
	P3R2	1	1.105	/	/
P4R1						1	0.635	/	/
	P4R2
		0	/	/	/
	P5R1
		0	/	/	/
	P5R2
		0	/	/	/
	P6R1
		0	/	/	/
	P6R2
		0	/	/	/
	P7R1					1	1.925	/	/
P7R2		1	2.115	/	/
	P8R1					2	0.315	1.765	/
P8R2		3	0.665	2.425	2.785

[ TABLE 8 ]

Fig. 6 and 7 are schematic diagrams showing axial aberrations and chromatic aberration of magnification of light having wavelengths of 650nm, 610nm, 555nm, 510nm, and 470nm passing through the imaging optical lens 20 according to the second embodiment. Fig. 8 is a schematic view showing curvature of field and distortion of light having a wavelength of 555nm after passing through the imaging optical lens 20 according to the second embodiment. The field curvature S in fig. 8 is a field curvature in the sagittal direction, and T is a field curvature in the tangential direction.

As shown in table 13, the second embodiment satisfies each conditional expression.

In the present embodiment, the imaging optical lens 20 has an entrance pupil diameter ENPD of 3.225mm, a full field image height IH of 3.000mm, and a diagonal field angle FOV of 42.40 °, and the imaging optical lens 20 satisfies the design requirements of a long focal length and a slimness, and has excellent optical characteristics with on-axis and off-axis chromatic aberration sufficiently corrected.

(third embodiment)

Fig. 9 is a schematic structural diagram of an imaging optical lens 30 according to a third embodiment of the present invention, which is basically the same as the first embodiment, and the same reference numerals as the first embodiment, and only differences will be described below.

Tables 9 and 10 show design data of the imaging optical lens 30 according to the third embodiment of the present invention.

[ TABLE 9 ]

Table 10 shows aspherical surface data of each lens in the imaging optical lens 30 according to the third embodiment of the present invention.

[ TABLE 10 ]

Tables 11 and 12 show the inflection points and the stagnation point design data of each lens in the imaging optical lens 30 according to the third embodiment of the present invention.

[ TABLE 11 ]

	Number of points of inflection	Position of reverse curvature 1	Position of reverse curvature 2	Position of reverse curvature 3
					P1R1	0	/	/	/
P1R2	1	0.915	/	/
					P2R1	1	0.915	/	/
P2R2
		0	/	/	/
P3R1						1	0.985	/	/
	P3R2	1	1.205	/	/
P4R1						1	0.685	/	/
	P4R2
		0	/	/	/
	P5R1
		0	/	/	/
	P5R2
		0	/	/	/
	P6R1
		0	/	/	/
	P6R2
		0	/	/	/
	P7R1					1	1.925	/	/
P7R2		1	2.105	/	/
	P8R1					2	0.245	1.735	/
P8R2		3	0.655	2.415	2.785

[ TABLE 12 ]

	Number of stagnation points	Location of stagnation 1	Location of stagnation 2
				P1R1	0	/	/
P1R2	1	1.435	/
				P2R1	1	1.425	/
P2R2	0	/	/
				P3R1	1	1.385	/
P3R2	0	/	/
				P4R1	1	1.335	/
P4R2	0	/	/
				P5R1	0	/	/
P5R2	0	/	/
				P6R1	0	/	/
P6R2	0	/	/
				P7R1	0	/	/
P7R2	0	/	/
				P8R1	2	0.415	2.495
P8R2	1	1.335	/

Fig. 10 and 11 are schematic diagrams showing axial aberrations and chromatic aberration of magnification of light having wavelengths of 650nm, 610nm, 555nm, 510nm, and 470nm passing through the imaging optical lens 30 according to the third embodiment. Fig. 12 is a schematic view showing curvature of field and distortion of light having a wavelength of 555nm after passing through the imaging optical lens 30 according to the third embodiment. The field curvature S in fig. 12 is a field curvature in the sagittal direction, and T is a field curvature in the tangential direction.

Table 13 below shows the numerical values corresponding to the respective conditional expressions in the present embodiment, in accordance with the conditional expressions described above. Obviously, the present embodiment satisfies the above conditional expressions.

In the present embodiment, the imaging optical lens 30 has an entrance pupil diameter ENPD of 3.268mm, a full field image height IH of 3.000mm, and a diagonal field angle FOV of 41.86 °, and the imaging optical lens 30 satisfies the design requirements of a long focal length and a slimness, and has excellent optical characteristics with on-axis and off-axis chromatic aberration sufficiently corrected.

[ TABLE 13 ]

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific embodiments for practicing the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in practice.

Claims

1. An imaging optical lens, comprising eight lens elements in order from an object side to an image side: a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element, wherein the first lens element has positive refractive power, the second lens element has positive refractive power, the fourth lens element has negative refractive power, the fifth lens element has positive refractive power, the sixth lens element has positive refractive power, the seventh lens element has positive refractive power, and the eighth lens element has negative refractive power; the total optical length of the imaging optical lens is TTL, the focal length of the imaging optical lens is f, the focal length of the second lens element is f2, the central curvature radius of the object-side surface of the seventh lens element is R13, and the central curvature radius of the image-side surface of the seventh lens element is R14, and the following relations are satisfied:

0.95≤f/TTL；

3.00≤f2/f≤5.50；

3.00≤(R13+R14)/(R13-R14)≤25.00。

2. the imaging optical lens according to claim 1, wherein the seventh lens has an on-axis thickness of d13, the eighth lens has an on-axis thickness of d15, and the following relationship is satisfied:

1.50≤d13/d15≤3.60。

3. the imaging optical lens according to claim 1, wherein the first lens has a focal length of f1, a central radius of curvature of an object-side surface of the first lens is R1, a central radius of curvature of an image-side surface of the first lens is R2, an on-axis thickness of the first lens is d1, and the following relationship is satisfied:

0.25≤f1/f≤1.08；

-2.48≤(R1+R2)/(R1-R2)≤-0.36；

0.05≤d1/TTL≤0.16。

4. the imaging optical lens according to claim 1, wherein a central radius of curvature of an object-side surface of the second lens is R3, a central radius of curvature of an image-side surface of the second lens is R4, an on-axis thickness of the second lens is d3, and the following relationship is satisfied:

-19.00≤(R3+R4)/(R3-R4)≤0.48；

0.02≤d3/TTL≤0.07。

5. the imaging optical lens according to claim 1, wherein the third lens has a focal length f3, a central radius of curvature of an object-side surface of the third lens is R5, a central radius of curvature of an image-side surface of the third lens is R6, an on-axis thickness of the third lens is d5, and the following relationship is satisfied:

-91.89≤f3/f≤1.99；

-62.08≤(R5+R6)/(R5-R6)≤0.61；

0.02≤d5/TTL≤0.09。

6. the imaging optical lens according to claim 1, wherein the fourth lens has a focal length f4, a central radius of curvature of an object-side surface of the fourth lens is R7, a central radius of curvature of an image-side surface of the fourth lens is R8, an on-axis thickness of the fourth lens is d7, and the following relationship is satisfied:

-1.01≤f4/f≤-0.30；

-1.17≤(R7+R8)/(R7-R8)≤-0.23；

0.02≤d7/TTL≤0.06。

7. the imaging optical lens according to claim 1, wherein the fifth lens has a focal length f5, a central radius of curvature of an object-side surface of the fifth lens is R9, a central radius of curvature of an image-side surface of the fifth lens is R10, an on-axis thickness of the fifth lens is d9, and the following relationship is satisfied:

1.02≤f5/f≤18.34；

-9.21≤(R9+R10)/(R9-R10)≤39.19；

0.02≤d9/TTL≤0.15。

8. the imaging optical lens according to claim 1, wherein a focal length of the sixth lens is f6, a central radius of curvature of an object-side surface of the sixth lens is R11, a central radius of curvature of an image-side surface of the sixth lens is R12, an on-axis thickness of the sixth lens is d11, and the following relationship is satisfied:

0.51≤f6/f≤4.54；

0.79≤(R11+R12)/(R11-R12)≤6.41；

0.02≤d11/TTL≤0.15。

9. the image-capturing optical lens according to claim 1, wherein the seventh lens has a focal length f7, an on-axis thickness d13, and satisfies the following relationship:

0.76≤f7/f≤5.60；

0.03≤d13/TTL≤0.19。

10. the imaging optical lens according to claim 1, wherein the eighth lens has a focal length f8, a central radius of curvature of an object-side surface of the eighth lens is R15, a central radius of curvature of an image-side surface of the eighth lens is R16, an on-axis thickness of the eighth lens is d15, and the following relationship is satisfied:

-1.77≤f8/f≤-0.48；

0.60≤(R15+R16)/(R15-R16)≤3.41；

0.02≤d15/TTL≤0.06。

11. an imaging optical lens according to claim 1, wherein the image height of the imaging optical lens is IH and satisfies the following relation:

f/IH≥2.58。

12. an imaging optical lens according to claim 1, wherein the image height of the imaging optical lens is IH and satisfies the following relation:

TTL/IH≤2.85。